1. Field of the Invention
The present invention is directed generally to a system for pipe inspection and repair and, more particularly, to a modular system for pipe inspection and repair in live-entry environments.
2. Description of the Background
Currently, between 800,000 to 1,000,000 leak repairs are carried out nationwide on gaslines, at a cost of between $750 to $1,250 each, including leak detection and pinpointing, excavation, repair and road restoration. Different external repair techniques and systems exist, but they cannot be deployed into live pipelines to assess the corrosion and sectional loss of pipes with a single excavation. If such a deployment were possible, it would reduce repair costs and provide a preventative maintenance tool.
Devices to access pipes require certain features which are lacking in prior techniques and systems. The need to access live pipes at no more than a 20xc2x0 entry-angle, as well as the need to travel through bends of 22.5xc2x0 sweep at 6 times the pipe diameter, impose constraints on the overall and/or individual length of the repair head of the inserted device. A prior camera inspection device, such as the Aries Gascam(copyright), can be used for entry angles approaching 90xc2x0, but such devices are only inspection, and not repair devices.
Because of a small, e.g. 4-inch pipe-diameter, and the presence of protruding taps, coupons and sharp edges, the hard diameter of the body of an inspection and repair device must be limited. Also, because such a device operates in a potentially explosive environment, e.g. a methane pipeline, the device needs to be designed to be safe and tolerant to failure modes. The complexity of the repair technology drastically impacts the overall system design in terms of power, interfaces, etc. The need to xe2x80x9cpreparexe2x80x9d the surface of the pipe for repair is driven by the type of repair technology used, which in turn has an impact on the device. Once repaired, if there is a requirement to test and prove that the repair has been effected, the device design needs to reflect that. One important aspect is the need to detect flaws once they have been located with a sensor systemxe2x80x94which must be done simply and reliably. In order to support modularity, tether and connector systems need to be designed so as to allow exchanges of modules in the field without rewiring and software modifications. Also, the operator interface to the device needs to be simple and rugged, because the device will be operated by various field personnel.
There are various prior art systems for patching pipes once a leak is detected and located. For example, external clamps are oftentimes used to repair leaks. However, the site where the leak is located must be excavated in order to attach an external clamp. Various internal repair methods have also been used. Split sleeve spot repair systems, such as Link-Pipe and Snap-Lok, are examples of various internal repair products.
Thus, there is a need for a pipe inspection and repair system that is faster, cheaper and uses a more convenient repair method than is possible with current methods. There is also a need for a system that is able to access and work within live gas mains from a single excavation and allow maximum travel from a single entry-point in both directions and must fit into and pass through, for example, 4 inch I.D. steel gas mains. There is a further need for a system that can reasonably negotiate bends, debris and protruding taps, operate safely within a pure methane environment, identify, mark, acquire, clean and repair defective area(s), and install a certifiable repair system. There is also a need for a system that can guarantee device retrieval under worst-case system failure and be modularly interchangeable with existing and future deployment and sensing/repair components and be easy to operate with minimal and manual operator interactions. There is also a need for a system that is deployable in the same manner as current camera and magnetic flux_leakage detector (MFL) inspection systems.
The present invention is directed to a multi-module pipe inspection and repair device. The device includes a base module, a camera module, a sensor module, an MFL module, a brush module, a patch set/test module, and a marker module. Each of the modules may be interconnected to construct one of an inspection device, a preparation device, a marking device, and a repair device. The present invention represents a substantial advance over prior pipe inspection and repair systems. The present invention has the following advantages, among others:
The system uses a multi-module exchangeable work-head system capable of viewing, inspecting, marking, cleaning and repairing pipe leaks or thinning pipe walls.
The multi-module pipe inspection and repair device of the present invention may interface to existing or new coiled-tubing (CT) deployment system sold by, for example, Maurer Engineering, Inc.
The hard module-diameter of the pipe repair device may be made to not exceed 3 inches O.D.
Inert materials (SS) with internal purging and nitrogen pressurization to 100 psig, as well as potting and immersion, are used as safing techniques.
The repair-head has a forward-looking live-video camera monitoring system.
The system has an independent visual flaw-marking emplacement (coupled to an MFL-head) and detection (on repair head) system.
The system is able to fine-position itself using a CT-unit to within +/xe2x88x921 inch, with an available independent stroke of less than 6 inches. The stroke may be achieved with an independent locomotion unit.
The internal pipe-surface is cleaned mechanically, preferably with a hardened steel brushing or impacting system.
The frontal cleaning-head and repair-modules of the pipe repair device are interchangeable.
The operator hard controls are integrated with existing CT, MFL and camera controls.
The present invention may reduce spot repair costs by as much as 25% for more than 2 repairs from a single excavation.
The present invention may perform 2 to 4 spot repairs per day from a single excavation.
The present invention may pass one or more 22.5xc2x0 bends, debris, and taps.
The present invention may operate safely in a pure methane environment.